The United States Civil War, already almost a year and a half old back in August of 1862, is about to get a whole lot bloodier.
Quoting from an application to include the South Mountain (Maryland) battlefield to the National Register of Historic Places:
"On September 4, 1862 General Robert E. Lee's Confederate Army of Northern Virginia, some 50,000 strong, waded across the Potomac River at White's Ferry and into Maryland for the first Confederate invasion of the North."
What is now known as the Maryland campaign began, as the Confederates waded the river to the tune of a song called "Maryland, My Maryland", which is now the Maryland State song.
A series of battles would result through September: among others, a battle at Harpers Ferry in what is now West Virginia (Harpers Ferry is noted for much more than John Brown's raid and is very worth a visit), a series of engagements now known as "The Battle of South Mountain" and a battle near Sharpsburg, Maryland, named after a tributary of the Potomac River called Antietam Creek.
I was in that area in March of this year, and will be traveling back later in September to explore the Civil War history of this area further.